Angle Between E field and conductor

In electrostatics, the angle between an E field and a good cinductor is 90 degrees.

In current carrying conductors, the E field assumes a slight angle with respect to that conductor. This is apparently true for DC and AC.

What factors influence this angle, and what is the range of angles that is likely to be encountered with good conductors like Cu, Al & Ag?

Thanks!

The component parallel to the conductor surface drives the current in the conductor. For metals this is a very small value.

Thanks for the reply.

I know that this component is very small. My question is, "How small?" What I am trying to learn is the range of angles over which this phenomenon occurs. Obviously, the low side is 90 degrees. What is the high side, and under what circumstances does it happen?

Bill

I think you need to define your question better.

If there is no ground plane and you have current flowing through resistive conductor, then field is parallel to the conductor.

If you have a ground plane with conductor running parallel to it energized at voltage V above ground (no current in the conductor), then field is exactly perpendicular to the conductor.

OK let me restate the problem.

A good conductor is carrying an AC OR a DC current in free space. Surrounding this conductor is an E field. (There has to be an E field or we would not have current flow.)

With a perfect conductor at DC, the angle between the conductor and the field is 90 degrees. With "good" conductors, the angle is slightly inclined from 90 degrees. What factors act to cause this? What is the range of angles that are likely to be encountered for DC and for AC in the MHz region?

Thanks! Bill

With a perfect conductor at DC, the angle between the conductor and the field is 90 degrees.

Click to expand...

By "at DC", do you mean a direct current flowing through the wire? If your talking about the E field (electric field) that causes this DC current, then the angle between the perfect conductor differential length and the E field at the same point is zero, and the E field is completely contained within the conductor.

If you mean by "at DC" that the conductor is at some DC potential relative to something else then, yes, there will be an E field perpendicular to the conductor, but this E field does not contribute to current flowing in the conductor. This E field will be perfectly perpendicular at all points along the conductor if it is perfectly straight and infinitely long. I don't know the answer as to how much field will exist which is not perpendicular to a finite length and straight conductor. It would be a very difficult problem to solve maxwells equations for those boundary conditions, but it may have been done. I guess also, there may be some experimental reports about this, but I have never seen any.